Krishanu Nath, a senior geologist, presented on energy critical elements with an emphasis on rare earth element (REE) exploration. Some key points: - Strategic minerals are essential for economic, defense, and technological purposes. REEs are sometimes labeled critical due to risk of supply issues and importance. - REEs have many applications including screens, lenses, motors, batteries, and more. They are found in carbonatites and other igneous rocks. - Exploration of REEs involves geological mapping, sampling, drilling, and analysis to define resources. Case studies in locations like India show REE mineralization in carbonatites.

1. Presented By:-
Krishanu Nath, Senior Geologist.
ENERGY CRITICAL ELEMENTS WITH A
SPECIAL EMPHASIS ON REE
EXPLORATION

2. Strategic Minerals is a broad-based category that constitutes various
minerals and elements (the majority of which are minor metals) which
a nation needs for military, industrial or commercial purposes that
are essential to the economy, defense, medicine, and for other reasons.
A mineral resource is labeled critical when the risk of supply
shortage and associated impact on the economy is higher than the
other raw materials.
Geography and availability of domestic supply often defines which
minerals are deemed "critical" for any particular region or country.

3. Geological Occurrences
Abundance / Grade
Exploration / extraction
techniques
Defence mechanization
Renewable energy
Medical use/ life style
products/ space technology
Imported from foreign countries Information technology
Geological scarcity
Lack of efficient extraction
techniques
Lack of scientific know how
Geopolitical scenario
Global economic scenario
Latest scientific
advancements
New Mineral Discoveries

4. Indian requirement for a mineral to be strategic are :-
Food security
Energy security / renewal and clean energy
National defense security
Space research
Information technology
E-automobiles

5. Factors Governing The Criticalness of a Mineral
Inadequacy of indigenous resources.
Constrain in supply chain from external sources.
Viability of substitution.
Recycling and criticality of its usage.
Defense preparedness of a country.
Availability of scientific know how.
 Geopolitical scenario.

7. Antimony
Beryllium
Cobalt
Fluorspar
Gallium
Germanium
Tungsten
The EU in June 2010 has published a list of 14 critical
raw materials listed below
“Critical Raw Materials for the EU”, Report of the RMSG Ad Hoc Working
Group on defining critical raw materials, June 2010
Graphite
Indium
Magnesium
Niobium
Platimum (group)
Rare Earth Elements
Tantalum

8. FOOD SECURITY

9. SCIENTIFIC KNOW HOW

10. GRAPHITE IS THE NEW STRATEGIC MINERAL

12. Rare Earth Elements
Rare earth elements or rare earth metals are a collection ofRare earth elements or rare earth metals are a collection of
seventeen chemical elements in the periodic table, namelyseventeen chemical elements in the periodic table, namely
scandium, yttrium, and the fifteen lanthanides namely:scandium, yttrium, and the fifteen lanthanides namely:
Lanthanum, Cerium, Praseodymium, Neodymium,Lanthanum, Cerium, Praseodymium, Neodymium,
Promethium, Samarium, Europium, Gadolinium, Terbium,Promethium, Samarium, Europium, Gadolinium, Terbium,
Dysprosium, Holmium, Erbium, Thulium, Ytterbium, andDysprosium, Holmium, Erbium, Thulium, Ytterbium, and
lutetium.lutetium.

13. Periodic Table

14. • Colour Screens
Nd • Camera Lens
LaCe
• Medical Services
Nd
Gd
Ce
Nd
Dy Tb
Eu
• Aerospace• Defence

15. •Petrolem Refining •High-Powered Motors
Nd TbDy
•Hybrid Vehicles
La Nd Dy
• Rechargeable
Batteries La
T
b
E
u
C
e
•Energy Efficient
Lighting
• Hardware
Components
Y
E
u
T
b

16.  REEs are sometimes referred to as
‘industrial vitamins' due to the fact that tiny
quantities of REEs when added to other
elements, tend to confer unique properties
on the latter.
 In many applications, moreover, no
substitute has been identified for a particular
REE.

17. It has recently started building the world’s biggest offshore wind
farm in Bohai Bay.
China is anticipating a quantum jump in its production of wind
energy from 12 giga-watts (GW) in 2009 to 100 GW in 2020 and is
constructing wind farms on an unprecedented scale.
Rare Earth Elements = Strategic Minerals

18. In order to produce each Mega Watt of wind power a wind
mill turbine requires up to 1 tone of permanent magnets.
The elements used in manufacturing of permanent magnets
are Nd, Dy and Tb, (REE), therefore China’s requirement of
REE is explained.
These metals are in short supply globally and thus the west is
in a danger of losing access to them as China’s domestic needs
soar.

19. Rare earth elements are not as "rare" as their name implies.
Thulium and lutetium are the two least abundant rare earth
elements - but they each have an average crustal abundance
that is nearly 200 times greater than the crustal abundance
of gold. However, these metals are very difficult to mine
because it is unusual to find them in concentrations high
enough for economical extraction.

20. CHARACTERISTICS OF REE
 REE behave incompatible and are HFSE, except Eu2+
. All have
lithophile behaviour as they concentrate in silicate minerals and
not in metals or sulphide bearing minerals.
 The total REE increases for 11 to 12ppm in primitive mantle to
~170ppm in upper crust.
 Both felsic and alkaline rocks have more REE. Carbonatite are
extremely enriched in REE. Only Sc is enriched in basalt.
 HREE are less compatible than LREE, compatibility with
minerals increases in opx-cpx-hbl-Sp-garnet.
 Large ionic radii 1.03 Å for La to 0.861 Å for Lu (1 Å =10-8
cm),
limits significant substitution of these rare earth elements into
minerals.

21.  More than 90% of heavy mineral sand deposits have average
grade of <1%.
 The REE in heavy mineral deposit are in monazite and has
thorium content of 5-7%, the REE are not recovered because
the cost of thorium disposal is very high.
 Dominant oxidation state of REE is 3+. All REE minerals are in
trivalent state. Lanthanum carbonate will precipitate at pH of
6.2, Lu at 6.4 and Y at pH 7.
 Fractionation of REE during weathering causes enrichment of
LREE and depletion of HREE.
 The relative mobility of HREE & LREE is influenced by
change of pH, alkanity & concentration of carbonates is ground
water. LREE are mobile in acidic fluids where as HREE favour
alkaline waters.
CHARACTERISTICS OF REE

22. GLOBAL RARE EARTH RESERVES BASE BY NATION

23. • The main source for REE is a suite of alkaline rocks dominated byThe main source for REE is a suite of alkaline rocks dominated by
Carbonatite which occure as intrusive or extrusive igneous rocksCarbonatite which occure as intrusive or extrusive igneous rocks
defined by mineralogic composition consisting of greater than 50defined by mineralogic composition consisting of greater than 50
percentage carbonate minerals. Carbonatites usually occurs as smallpercentage carbonate minerals. Carbonatites usually occurs as small
plugs within zoned alkalic intrusive complexes, or as dykes, sills,plugs within zoned alkalic intrusive complexes, or as dykes, sills,
breccias, and veins.breccias, and veins.
• The main minerals which contains REE are Bastnaesite (Ce,La,Y)Co3FThe main minerals which contains REE are Bastnaesite (Ce,La,Y)Co3F
Pyrochlore(Na,Ca)2Nb2O6 (OH,F) Monazite(Ce,Le,Th)PO4 &Pyrochlore(Na,Ca)2Nb2O6 (OH,F) Monazite(Ce,Le,Th)PO4 &
Carbocernaite (Ca,Na)(Sr,Ce,Ba)(CO3)2.Carbocernaite (Ca,Na)(Sr,Ce,Ba)(CO3)2.
SOURC
E
Mountain Pass mine, California

24. Bastnaesite hosted by carbonatite is now the primary source ofBastnaesite hosted by carbonatite is now the primary source of
world production eg. Mountain Pass, USA; Mount Weld, Westernworld production eg. Mountain Pass, USA; Mount Weld, Western
Australia; Quebec, Canada; Cerro Manomo, Bolivia; Tundulu,Australia; Quebec, Canada; Cerro Manomo, Bolivia; Tundulu,
Malawi; Kibina, Kola Penninsula; Russia etc. Bulk of theMalawi; Kibina, Kola Penninsula; Russia etc. Bulk of the
remainder REE resource is contained in monazite/ xenotime fromremainder REE resource is contained in monazite/ xenotime from
Australia, Brazil, China, India, Malayasia, South Africa, SriAustralia, Brazil, China, India, Malayasia, South Africa, Sri
Lanka, Thailand and USA.Lanka, Thailand and USA.
Recently, massive deposits of rare earths have been found in theRecently, massive deposits of rare earths have been found in the
mud on Pacific floor. Japanese geologists have found rich depositsmud on Pacific floor. Japanese geologists have found rich deposits
in samples taken at more than 2000 km from the Pacific Mid-in samples taken at more than 2000 km from the Pacific Mid-
Ocean Ridge between 120 degrees to 180 degrees longitude .Ocean Ridge between 120 degrees to 180 degrees longitude .
 Beach placers.Beach placers.

25. The Bayan Obo REE-Nb-Fe deposit hosts the world’s largest
known REE resources.
The deposit consists of replacement bodies hosted in
dolomite marble and less important in K-rich slate.
Hand specimen of micro- folded banded ore consisting of irregular to
lenticular layers of monazite (m), granular hematite (he), and fluorite
(fl).

26.  Grades at Bayan Obo are 3 to 6% REO; reserves are at
least 40 Mt, possibly considerably more.
 The second major source of Chinese REE is “ion-
adsorption ores” in lateritic…
Th & U found in association with
REE makes the mining waste toxic.
Mining cost of lateritic source is very less.
Worker fills ceramic pots with REE
precipitates.
The home of REE wellcomes you.

27. REE

28. STAGES OF EXPLORATION OF REE DEPOSITS
 Geological mapping and field studies.
 Sampling by pitting and trenching at regular interval.
 Petrographic and mineralogical studies.
 Chemical analysis of major and trace elements and REE.
 Subsurface drilling.
 Interpretation of exploration data.
 Firming up resources and subsurface deposit model.

29. REE INVESTIGATION CASE STUDIES

30. LOCATION MAP OF KAMTHAI AREA

32. GRID SAMPLING OF KAMTHAI ML AREA

33. GEOCHEMICAL CONTOUR MAP OF LREE,
KAMTHAI, BARMER, RAJASTHAN

34. LVS OF SOUTHERN PART OF KAMTHAI
PLUG

35. RESULTS OF BSE
STUDIES•Acicular synchysite (Ce) mantled by bastnaesite (Ce) is intergrown
with calcite and Mn-oxides
•The ancylite phase is a solid solution between ancylite and
bastnaesite (La) and contains 12-18 wt % SrO and 28-40 wt % La2O3
and 1-9 wt % Ce2O3
Synchysite
ap
mnox
bst

36. EPMA DATA (GSI)

37. FIELD OCCURRENCES OF
CARBONATITES
Carbonatites occurring as plug has characteristic
panther skin texture, whereas sills/dykes show
golden yellow colour, sometimes with elephant skin
like weathering

38. REE
GEOCHEMISTRY
 The highest values for La, Ce, Pr, and Nd are 7.33%, 8.12 %, 0.53
% and 1.18 % respectively.
 The average of 215 samples within the plug body for La, Ce, Pr and
Nd are 1.29 %, 1.58 %, 0.12 % and 0.3 % respectively.
 The Sm and Eu highest values are 821 ppm and 213 ppm where as
averages are 135 ppm and 43 ppm respectively.
 The highest LREE (La+ Ce+ Pr+ Nd+ Sm+ Eu) are 17.31 % and
total REE are 17.39 %.

39. RESOURCE ESTIMATION
Specific gravity of samples varies between 2.85 to 2.97 but
for carrying out resource calculation we have considered
the lowest specific gravity of 2.85.
The total resource under all categories together for LREO
ore (of the carbonatite plug) is 15.32 million tons at 0.5%
cut-off having 1.58% average grade.
According to UNFC(2009) the voluminous reserve of
Kamthai deposit comes under 111.

40. LOCATION MAP OF THE
AREA:
Map compiled by Kaur et al 2012,
University of Punjab.
Published in Journal of
Petrology vol. 53.

41. BACKGROUND INFORMATION
 The present FSP Item – Spin off of the STM, FS 2010-2012
(Neogi et al. , 2012) in the albite rich Gothara Granites.
 Out of 26 nos. of samples 04 nos. of samples yielded
anomalous REE, from 1077.35 to 1685.56 ppm.
 During FS 2013-15 LSM of 20 sq km and DM of 1.5 sq km
carried out, which led to the identification of a REE
mineralized zone of 600 m X 250 m in the South of Gothara
village.
 Drilling has been proposed to ascertain the subsurface
continuity of the REE anomaly zone during the current FS.
 Another REE anomalous area identified during LSM in
Rajota village, is being taken up for DM during the current FS.

42. Map prepared by Neogi et al. Geologist STM I Division.

43. Intrusives
Quartz veins
Hydrothermal breccia
Gothara Granite
Khetri Group
(Proterozoic)
Unit -8 Amphibolite dykes
Unit -7 Calc silicate, marble.
Unit -6 Micaceous quartzite.
Unit -5 Garnetiferrous mica schist.
Unit -4 Amphibole quartzite
Unit -3 Magnetite quartzite
----------------------------Unconformity--------------------
Basement
(Archean)
Unit -2 Staurolite sillimanite schist
Unit -1
Feldspathic and ferruginous
quartzite.
Litho-Stratigraphic Succession of Gothara Granite Area, NKFB
After Neogi et al., 2013.

44. Area for DM
FS 2013-15

49. DRILLING
EXPLORATION

50. Prospective
Zone for drilling
in FS 2015-16.

58. BSE images showing REE bearing
phases in Gothara Granite.
i.Synchysite.
ii. Bastnasite.
iii.Thorbastnasite.
iv.Allanite.

59. Gothara Granite oxide analyses data plotted in
Feldspar triangle plot after O’Conner 1965.
Gothara Granite oxide analyses data plotted in
TAS diagram after Middlemost 1994.
PETROCHEMICAL CLASSIFICATION OF GOTHARA GRANITE

60. Gothara Granite oxide analyses data plotted
in R1 – R2 plot after De la Roche et al., 1980.
Gothara Granite oxide analyses data plotted
in B –A plot after Villaseca et al.1998.
PETROCHEMICAL CLASSIFICATION OF GOTHARA GRANITE

61. i. WPG – within plate granites.
ii. VAG – volcanic arc granites.
iii. COLG – collision granites.
iv. ORG – ocean ridge granites.
TECTONIC DISCRIMINATION DIAGRAM OF GOTHARA
GRANITE AFTER PEARCE et.al.,1984.

62. Tectonic discrimination diagram of
Gothara Granite after Whalen et al., 1987
plotting zirconium content against
10000*Ga/Al.
Tectonic discrimination diagram of
Gothara Granite after Whalen et al.,
1987 plotting agpaitic index against
10000*Ga/Al.
TECTONIC DISCRIMINATION DIAGRAM OF GOTHARA
GRANITE AFTER WHALEN et. al., 1987
A
I & S
I & S
A

63.  Majumdar (1976-78) reported Siwana suite is enriched in
niobium, yttrium, lanthanum and zirconium and indicate
250 ppm Nb, 500 ppm La, 700 ppm Y and greater than
1000 ppm Zr on average.
 Rastogi and Mukherjee (2013-14) carried out STM and
sampling of the rhyolites, granites, microgranites and tuffs in
Siwana has indicated anomalous REE values with ∑REE
ranging from 513 ppm to 3719 ppm.
Siwana Ring Complex

64. GeoloGical map of Siwana RinG complex and Study aRea
Study area
(Phulan block)
Geological map of Siwana
Ring Complex(GSI)

65. Mapped by Das et al.,2014-15

66. diffeRent litholoGy of phulan aRea
Siwana Rhyolite:
Fine grained, porphyritic in nature.
Mainly composed of embayed phenocrysts of k-feldspar and quartz.
Aegirine are invariably present as the characteristic constituents of the groundmass.
Vesicles are common in rhyolite, where they are commonly filled by secondary
calcite and quartz.
Phulan rhyolite showing elongated vesicles
in the direction of flow
Phulan rhyolite showing embayed
phenocrysts of k-feldspar

67. Siwana Granite:
Leucocratic, medium to coarse grained.
Intrusive nature within Siwana Rhyolite.
Mainly composed of alkali feldspar, quartz, alkali pyroxene and alkali amphibole.
It shows hypidiomorphic texture, perthite texture and rapakivi texture.
Siwana granite showing altered feldspar
and randomly oriented aegirine.
Siwana granite showing rapakivi texture

68. Microgranite:
The microgranite dykes cutting across the granite porphyry and trends ranging from N-S
to E-W.
Microgranite dykes are medium grained and dominantly composed of quartz, feldspar
and aegirine.
Felsite:
7 nos. Felsite dykes are identified near Phulan
village. Felsite dykes shows intrusive relation with
the rhyolite.
Felsite dykes: Strike length varies from 30 m to
200 m ;Width varies from 0.10 m to 2.50 m
Felsite dykes are greenish grey colour, fine
grained and dominantly composed of quartz,
feldspar, aegirine and opaques.

69. Details of samples anD analytical results
Nature of
Sampling
Location Lithology
No of
Sample
collected
Analytical result ΣREE+Y in
ppm
Min Max Average
Bed rock
grab
Phulan - Devra
Granite 16 1365.80 4701.11 2673.32
Felsite 10 6021.46 21936.71 11774.91
Rhyolite 4 1509.39 4660.19 2339.81
Channel Phulan - Devra Felsite 30 1769.10 34932.73 13844.08
30 nos. bed rock grab samples are collected from all litho variant.
30 nos. of channel samples are collected from all felsite dykes.
Total 9 nos. channel put in felsite dykes with sample length varies
from 10-50cm.
Each channel put in 40-60m interval across each felsite dykes.

70. petrography of felsite Dykes
Felsites are fine grained and composed of quartz, k-feldspar,
plagioclase, aegirine, zircon and opaques.
Felsites are showing intergranular texture, intergrowth texture, perthite
texture.
Photomicrograph of felsite dyke showing aggregates of quartz, k-feldspar and aegirine grain

71. geochemistry of felsite Dykes

72. Detail analytical results of felsite Dykes channel
samples
∑REE+Y LREE HREE
Min Max Avg. Min Max Avg. Min Max Avg.
10080.2 22724.6 17052.2 6114.08 12224.3 9598.85 3966.08 11571.3 7453.29
Nb Zr Hf
Min Max Avg. Min Max Avg. Min Max Avg.
732.00 1385.00 1084.57 5836.00 9944.00 8774.42 215.27 383.81 332.05
U Th
Min Max Avg. Min Max Avg.
38.29 70.53 53.90 155.00 571.00 307.85
(All values in ppm, Number of samples: 07)

76. Sample Name: FD-1 ΣREE+Y: 1.06%
Monazite: La2O3; 31.63%, Nd2O3; 5.25%
Ce2O3; 31.61%, P2O5;29.27%, ThO2; 0.50%
Chevkinite: SiO2;19.2%, MnO;3.2%,
Ti02;17.86%, FeO; 7.2%, RE2O3; 46.6%
Eudialyte: SiO2; 48.3%, Nb2O3; 2.4%,
ZrO2;12.76%, MnO; 7.1%, CaO;2.4%,
RE2O3; 7.8%
Zektzerite: SiO2; 45.75%, ZrO2; 30.57%,
CaO; 11.48%
Eudialyte: SiO2; 49.8%, Nb2O3; 0.63%
ZrO2; 13.24, MnO; 5.1%, CaO: 3.6%,
RE2O3; 10.5 %
Zektzerite: SiO2; 61.3%, ZrO2; 33.35%
Monozite
Zektzerite
Eudialyte
Chevkinite
Zektzerite
Eudialyte

77. Allanite
PARISITE
PARISITE
PARISITE
ZIRCON
Parisite: F: 8.3, La2O3: 12.1, Nd2O3: 15.9
Ce2O3: 31.9,CaO: 3.5, Pr2O3: 4.2
Zircon: SiO2: 30.9%,ZrO2: 46.7%
Y2O3: 3.2, La2O3: 1.6, Nd2O3: 2.8 Ce2O3: 4.2
Allanite: SiO2: 29.9%, Al2O3: 8.8
CaO: 9.25% La2O3: 10.1, Nd2O3: 1.9,
FeO 18.5, MnO: 2.28 Ce2O3: 10.8
Sample Name: FD-1 ΣREE+Y: 1.06%

78. REE
Minerals
Grain
size(micron)
Grain shape Mode of Occurence
Monazite 50-200
Euhedral-
Subhedral
Larger grains occupied at the grain
boundary of aegirine - k feldspar, aegirine -
qtz whereas smaller grains occur as inclusion
within aegirine and k feldspar
Parisite 15-50
Euhedral-
Subhedral
At the grain boundary of aegirine - k
feldspar, aegirine - quartz, inclusion within
quartz and k-feldspar
Allanite 50-200
Euhedral-
Subhedral
At the grain boundary of quartz- aegirine
Tritomite 150-250 Anhedral
At the grain boundary of k feldspar –
aegirine
Chevkinite 50-75 Anhedral At the grain boundary of quartz – aegirine
Zektzerite 50-200
Anhedral-
Subhedral
At the grain boundary of quartz – aegirine
Eudialyte 50-150
Euhedral-
Subhedral
At the grain boundary of quartz - aegirine
and k feldspar – aegirine
characterization of ree bearing minerals

79. World class concentrations of REEs have
been discovered in the Khanneshin deposit
in Helmand province of Afghanistan with a
resource position of one million
Tones.
oElements such as Pr, Ce, La and Nd can be
extracted from these minerals but the
problems is with infrastructure .
Khanneshin REE deposit, Afghanistan

80. Khanneshin
Helmond Province
Afghanistan
Helmand Province, Afghanistan:
huge REE potential

81. USGS team that is credited with discovering
REE resources in Helmand Province, Afghanistan;
Robert Tucker is a member of the team

82. Like the soldiers, USGS geologists sport helmets and
heavy ceramic flak vests even as they discuss the
mining potential of a large outcrop. Each investigation
is limited to an hour so that hostile forces do not have
time to organize and descend.
Image courtesy:
Robert Tucker, USGS, 2011

83. With a perimeter established, marines allow
geologists to remove their helmets, but the
human chain of soldiers continually encircles
them as they pursue clues in the rock
Image courtesy:
Robert Tucker, USGS, 2011

84. The scientists finally discover a promising
mustard-colored rock deposit. Later, lab work
confirmed the geologists' prediction: the
enrichment of LREEs in this sample is on par
with ore mined at Bayan Obo in China
Image courtesy:
Robert Tucker, USGS, 2011

85. The yellow phenocryst mineral is a
complex aggregate of khanneshite,
synchysite, barite, strontianite,
dolomite and an unidentified Sr-rich
orthocarbonate.
Image courtesy:
Robert Tucker, USGS, 2011

86. Distribution of average
ΣREY contents for surface
sediments (<2 m in depth)
in the Pacific Ocean.
Yasuhiro Kato et al 2011
Contours represent 3
He
anomalies of mid-depth seawater
REY-rich mud with average REY >400
ppm is designated as a potential
resource in this study
colors correspond to the dominant
origin of surface sediments